Logic Pro (X) ESX24 loses instruments


I am working in Logic and on 3 tracks the ESX24 forgets the instrument I had previously chosen and reverts to some default sound. Where it would normally display the name of the instrument, there are 3 small dots. This happens whenever I close and reopen the project, or whenever I open another project without closing this one. On the other tracks the ESX is working normally. Any ideas about what I could try?